1. Field of the Invention
This invention relates to a phonographic pick-up cartridge construction employing a pre-dimensioned stylus arm support wire and mounting means therefor.
2. Description of the Prior Art
Among the components of a record player, the pick-up system, i.e., the tonearm and pick-up cartridge, has the greatest influence on the quality of the reproduced sound.
Conventional pick-up cartridges may be broadly divided into the moving magnet (MM), moving iron (MI), and moving coil (MC) types. The present invention is concerned with an improved pick-up cartridge of the former two types, particularly of the kind wherein the vibrating system is supported by a tensioned wire extending through and compressing a rubber damper disposed at the forward end of the cartridge.
In conventional pick-up cartridges of this kind, the support wire is connected to a cantilevered stylus arm, and is secured to the stylus support by a set screw. To place the rubber damper in operational readiness, it is necessary to first apply a compressive stress thereto.
Specifically, as shown in FIG. 1, one end of a wire 2 is secured to the end portion of a cantilevered stylus arm 1. The other end of the wire extends into and is fixed within a sleeve 3 mounted in a stylus support 4. An adjustment screw 5 is threaded into the stylus support to axially fix the sleeve in the support. During assembly, a predetermined tension W is applied to the wire, the sleeve 3 is pinched or clamped in position in the support 4 with the screw 5, and the excess wire extending out of the sleeve is cut off. In this manner, an initial compressive stress is applied to the resilient damper member 6 disposed between the stylus arm and the support.
Such a pick-up cartridge, however, comprises a number of minute parts whereby the fabricating process is complicated, and substantial time is required to accomplish the initial tension control operation for each individual pick-up cartridge.
Further, the stylus support is relatively costly due to the necessary dimensional accuracy thereof. It is typically manufactured on a lathe out of a brass block, and must be provided with an opening for the sleeve 3, a threaded aperture for the screw 5, and a smooth outer surface. These fabricating operations are all manually effected, thereby resulting in wide tolerance variations and a high reject ratio.